Abstract
Abstract: :
Purpose: To evaluate clinical outcomes and ocular aberrations during the 6 months after wavefront–guided laser in situ keratomileusis (LASIK) (Zyoptix, Bausch & Lomb) for myopia and myopic astigmatism. Methods: This prospective study comprised 37 eyes of 22 patients treated with wavefront–guided LASIK who were available for evaluation during the six months after surgery. Mean age was 34,56 ± 19,72 years old and mean preoperative spherical equivalent manifest refraction was –3.35 diopters (D) ± 1.44 (SD). Wavefront–guided ablation was performed using Zyoptix System (Bausch & Lomb). Treatment was calculated with Zylink software program and surgery was performed with the Chiron Technolas 217 Z flying–spot excimer laser system (Bausch & Lomb). The safety, efficacy and evolution of ocular aberrations after customized ablation were evaluated. Results: Six months postoperatively, mean spherical equivalent manifest refraction was – 0.32 (D) ± 0.31 (SD). Uncorrected visual acuity (UCVA) was 20/20 or better in 96,37%, 20/16 or better in 53,57% and 20/12.5 in 3,57% of eyes. There was no lost lines of BSCVA, 50% of eyes gained 1 line and 3.6% gained 2 lines of BSCVA. An spherical equivalent (SE) of ± 0.50 D and ± 1.00 D of intended correction was achieved by 96,4% and 100%, respectively, at 6 months. The safety index was 1.20 and the efficacy index 1.14. Wavefront analysis during the first six months after surgery showed a non–systematic fluctuation of ocular aberrations, and at 6 months, there was a significant reduction of second order aberrations due to reduction of defocus and astigmatism, specially astigmatism Z220. Higher order aberrations increased significantly due to 4–th and 5–th order aberrations while 3–order aberrations did not show a significant increase, except for coma Z330. Conclusions: Wavefront–guided LASIK is a refractive surgery technique with excellent safety and efficacy indices. Customized ablation successfully treated second order aberrations and was able to avoid significant increase in 3–rd order aberrations. Further refinements in defining the ablation algorithms for treatment of these aberrations, specially 4–th and 5–th orders, may increase their correction, improving the results.
Keywords: laser • refractive surgery: LASIK • refractive surgery: other technologies